Conventional power driven tools for socket structure are normally driven either manually or by electrical power. Electrical tools are usually connected to pneumatic power source to take advantage of the output of compression air to provide constant torque to achieve locking operations. Pneumatic tools usually use torque connecting shaft to output torque to achieve locking purpose.
Referring to FIG. 1, illustrated is a conventional torque connecting shaft 91 which includes a protruded sleeving part 911 and a sleeving hole 912 provided at each end of the shaft, for connecting to a pneumatic tool and for engaging with a socket. This type of conventional torque shaft can only work on a straight line and if the socket required to be locked is located away from the straight line, it will be difficult to reach the socket. Besides, when the torque connecting shaft 91 is connecting with the socket, the protruded sleeving part 911 engages with the socket. It is not convenient to adjust a steel ball 913, so that when engaging with the socket, it will not be easy to operate speedily. Referring to FIG. 2, illustrated is another conventional connecting shaft, arranged for a socket to easily engage onto the shaft, but the protruded sleeving part can only be operated in straight direction and cannot turn to the other angular positions.
Referring to FIGS. 3 and 4, another connecting shaft is shown and allows a limited turning angle, a driven head is disposed at one end of the connecting shaft, a positioning ball is disposed on the driven head at a desirable location, a concave part is located between the driven head and the positioning ball. Referring to FIG. 3, in operation, the connecting shaft and the socket can be connected in a straight manner, the socket can also turn within a limited angle on the connecting shaft as referring to FIG. 4. When in a straight manner, the positioning ball can help to position the tool. But when it operates in the manner of angle turning, the connection between the connecting shaft and the socket depends only on a simple insertion mechanism, there is no element to help positioning, if the operating angle is not suitable the socket will easily fall apart from the connecting shaft. Even though the positioning ball can achieve positioning function when operating in a straight manner, the socket can still detach from the connecting shaft when the force acting on the socket from a pneumatic tool is bigger than the positioning force of the ball. Thus will affect safety of using the tool.